The prior art teaches various designs for electrochemical cells in which a sheet-like anode plate, sheet-like cathode plate, and separator sheets are spirally wound in the form of a coiled core which can be inserted into a metal casing or can. U.S. Pat. Nos. 4,699,856, No. 4,702,978, and No. 4,707,421 disclose various designs proposed for spirally wound electrochemical cell cores.
During the discharge of an electrochemical cell, diffusion of ions .from the anode into the cathode occurs. Minimization of the diffusion distance is typically achieved in a spirally wound cell by providing a coiled core in which the cathode material has anode material on both sides of it. Separator sheets can be provided which permit the passage of ions and gas.
Some kinds of spirally wound cores may be fabricated by conventional machines. One such conventional machine is sold under the trade name "Nickel Cadmium - Battery Winder" in the United States of America by Weiler Engineering Company, 2445 East Oakton Street, Arlington Heights, Ill. 60005 U.S.A. While this machine functions well in fabricating spirally wound cores of the type for which it is designed, the winding is intermittent and thus relatively slow. Accordingly, there is a need for even better performance and greater versatility.
It would also be desirable to provide an improved method and apparatus for winding an electrochemical cell core in an efficient manner that would have a relatively low likelihood of operational failure.
Further, it would be advantageous if such an improved method and apparatus operated to positively engage and manipulate the core components, including the anode plate, cathode plate, and separator sheets, so as to insure proper registration and winding of the components.
Additionally, it would be beneficial if such an improved method and apparatus could readily accommodate variations in the lengths of the components. It would also be desirable if such an improved method and apparatus could readily accommodate variations in the thicknesses of the components.